Not always so terrible when a player hits a QB that is sliding. Couple of random thoughts on it and targeting

1) it's such an unnatural football play. It happens so rarely that it's hard to get ticked at a player for not executing it correctly.
2) The timing isn't always so simple. A Defender has no idea when a QB is going to slide.
3) the act of sliding actually places the head in a position that the defender isn't anticipating if the QB stays upright.
4) Tanner ALMOST slid on another play later in the game. You could tell he was about to pull up but then decided to get a couple of extra yards. This can cause an advantage to the QB because Defenders these days don't want to get a penalty.
5) think people either don't know or don't remember how fast things happen in football and how unforseen movements by the Offensive players can create situations that the D is not intending.
6) I know there's a really dangerous way to "lead with the head" and what they are TRYING to prevent but just by virtue of where are heads are located on our bodies and how they are situated, you're practically "leading with the head" on every single play.